1. Field of the Invention
The present invention relates to a method of assembling a light bulb, and more particularly to a method of assembling an airtight LED light bulb.
2. Description of Related Art
With reference to FIG. 6, a conventional LED light bulb has a heat-sink housing 60, an LED device, a bulb envelope 70, a stem device and a cap 80. The heat-sink housing 60 is made of metal, has a top edge and is used to dissipate heat generated from the LED device. The bulb envelope 70 is securely combined with the top edge of the heat-sink housing 60. The LED device is mounted in the heat-sink housing 60 and the bulb envelope 70. The stem device is securely connected with the LED device and is detachably mounted in the heat-sink housing 60. The cap 80 is mounted securely around the stem device. However, the conventional LED light bulb has the following drawbacks.
1. Easy Damage to the LED Device:
Because the heat-sink housing 60 and the bulb envelope 70 are combined with each other with glue, gaps may be formed between the heat-sink housing 60 and the bulb envelope 70. Gaps may also be formed between the stem device and the heat-sink housing 60, because the stem device is detachably mounted in the heat-sink housing 60. The moisture in the environment may enter the LED light bulb and damage the LED device via the gaps, and the reliability of the LED device is reduced. The PCB or conductors of the LED device are easily oxidized or dampened. Consequently, the lifespan of the LED light bulb is shortened.
2. Weak Versatility of the Heat-Sink Housing 60:
A shape of the heat-sink housing 60 has to correspond to that of the bulb envelope 70 to facilitate the assembly of the heat-sink housing 60 and the bulb envelope 70. However, to change the shape of the heat-sink housing 60 requires new molds, and this increases manufacturing cost and is not versatile.
3. Inefficient Illumination:
A coating of an inner surface of the bulb envelope 70 helps light reflection and enhances illumination. However, a surface area of the inner surface of the bulb envelope 70 is small, and the heat-sink housing 60 blocks part of light. Accordingly, the illumination of the conventional LED light bulb is inefficient.
4. Poor Insulation:
The heat-sink housing 60 is usually made of metal to help dissipate heat. However, the metallic heat-sink housing 60 is not insulating, may cause users to get an electric shock and is not safe.
To overcome the shortcomings, the present invention provides a method of assembling an airtight LED light bulb to obviate the aforementioned problems.